Super Saver is a Carnival fare type. Carnival's help pages say it may be priced lower than Early Saver but comes with more restrictions and does not include a cabin assignment: you choose the type of cabin and Carnival decides where on the ship it is. Like Early Saver, it requires a non-refundable deposit at the time of booking.
The trade-off shows up after you book. Super Saver is not covered by Carnival's Early Saver price protection, so if the fare for your sailing falls later, there is no program to claim the difference through. It works the other way too: if you hold an Early Saver booking and a Super Saver fare appears below what you paid, Carnival does not count that lower Super Saver price toward your claim.
That makes the choice between the two a real one. Super Saver can be the cheaper fare on the day you book. Early Saver can cost more up front, but it lets you claim later drops up to 2 business days before sailing, repriced if you have not paid in full and as onboard credit if you have.
The full rules, with Carnival's own terms linked, are on the Carnival price drop policy page. How often Carnival fares move after booking is on the Carnival price data page.
